move to archive from crc32 package

Move over to using the `archive` package for our crc code instead of the `crc32` one. This package also has a tar decoder, a zip encoder, and pure-dart inflate and deflate algorithms. The zip encoder will be useful for uploading to the web store.

Our tests run, and I can git clone several projects, including Spark itself (takes about ~1 minute).

@gaurave